Limits...
Time-domain spectroscopy in the mid-infrared.

Lanin AA, Voronin AA, Fedotov AB, Zheltikov AM - Sci Rep (2014)

Bottom Line: Here, we show that, with a combination of advanced ultrafast technologies and nonlinear-optical waveform characterization, time-domain techniques can be advantageously extended to the metrology of fundamental molecular motions in the mid-infrared.In our scheme, the spectral modulation of ultrashort mid-infrared pulses, induced by rovibrational motions of molecules, gives rise to interfering coherent dark waveforms in the time domain.These high-visibility interference patterns can be read out by cross-correlation frequency-resolved gating of the field in the visible generated through ultrabroadband four-wave mixing in a gas phase.

View Article: PubMed Central - PubMed

Affiliation: 1] Physics Department, International Laser Center, M.V. Lomonosov Moscow State University, Moscow 119992, Russia [2] Russian Quantum Center, ul. Novaya 100, Skolkovo, Moscow Region, 1430125 Russia.

ABSTRACT
When coupled to characteristic, fingerprint vibrational and rotational motions of molecules, an electromagnetic field with an appropriate frequency and waveform offers a highly sensitive, highly informative probe, enabling chemically specific studies on a broad class of systems in physics, chemistry, biology, geosciences, and medicine. The frequencies of these signature molecular modes, however, lie in a region where accurate spectroscopic measurements are extremely difficult because of the lack of efficient detectors and spectrometers. Here, we show that, with a combination of advanced ultrafast technologies and nonlinear-optical waveform characterization, time-domain techniques can be advantageously extended to the metrology of fundamental molecular motions in the mid-infrared. In our scheme, the spectral modulation of ultrashort mid-infrared pulses, induced by rovibrational motions of molecules, gives rise to interfering coherent dark waveforms in the time domain. These high-visibility interference patterns can be read out by cross-correlation frequency-resolved gating of the field in the visible generated through ultrabroadband four-wave mixing in a gas phase.

No MeSH data available.


Related in: MedlinePlus

Cross-correlation frequency-resolved optical gating traces (a–f) of resonant mid-IR pulses with a central wavelength λ0 equal to (a, b, c, d) 4.25 μm and (e, f) 6.20 μm and an input pulse width τ0 = 160 fs transmitted through 1.5 m of atmospheric air: (a, c, e) experiments and (b, d, f) simulations using Eqs.(1)–(6). The spectrum calculated using only the properly normalized envelopes of the P and R branches of the rotational spectrum of the antisymmetric stretch of a CO2 molecule is shown by the pink dashed line. (g, h) The spectra of resonant 160-fs mid-IR pulses with a central wavelength of (g) 4.25 μm and (h) 6.20 μm transmitted through 1.5 m of atmospheric air. (i) The spectral profiles of the absorption coefficient and refractive index of the antisymmetric stretch of a CO2 molecule calculated with the full model of the antisymmetric stretch band of CO2 (in pink and blue, respectively) and using only a properly normalized envelope of this band, without individual rovibrational lines (in green and orange). (j) The absorption coefficient (pink) and refractive index (blue) of water vapor calculated with the full model of the H–O–H bending mode of a water molecule.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4202239&req=5

f3: Cross-correlation frequency-resolved optical gating traces (a–f) of resonant mid-IR pulses with a central wavelength λ0 equal to (a, b, c, d) 4.25 μm and (e, f) 6.20 μm and an input pulse width τ0 = 160 fs transmitted through 1.5 m of atmospheric air: (a, c, e) experiments and (b, d, f) simulations using Eqs.(1)–(6). The spectrum calculated using only the properly normalized envelopes of the P and R branches of the rotational spectrum of the antisymmetric stretch of a CO2 molecule is shown by the pink dashed line. (g, h) The spectra of resonant 160-fs mid-IR pulses with a central wavelength of (g) 4.25 μm and (h) 6.20 μm transmitted through 1.5 m of atmospheric air. (i) The spectral profiles of the absorption coefficient and refractive index of the antisymmetric stretch of a CO2 molecule calculated with the full model of the antisymmetric stretch band of CO2 (in pink and blue, respectively) and using only a properly normalized envelope of this band, without individual rovibrational lines (in green and orange). (j) The absorption coefficient (pink) and refractive index (blue) of water vapor calculated with the full model of the H–O–H bending mode of a water molecule.

Mentions: Typical FWM XFROG traces of mid-IR waveforms modulated by the rovibrational modes of carbon dioxide molecules and atmospheric water vapor are shown in Figs. 3a–3f. The difference between these traces and the XFROG traces of mid-IR pulses tuned off all the molecular resonances (Figs. 2b, 2c) is striking. Unlike off-resonance FWM XFROG traces, determined by an appropriate convolution of the mid-IR and reference pulses, the XFROG traces of mid-IR pulses tuned on a resonance with molecular modes exhibit well-resolved fringes along with a complex ring-down structure.


Time-domain spectroscopy in the mid-infrared.

Lanin AA, Voronin AA, Fedotov AB, Zheltikov AM - Sci Rep (2014)

Cross-correlation frequency-resolved optical gating traces (a–f) of resonant mid-IR pulses with a central wavelength λ0 equal to (a, b, c, d) 4.25 μm and (e, f) 6.20 μm and an input pulse width τ0 = 160 fs transmitted through 1.5 m of atmospheric air: (a, c, e) experiments and (b, d, f) simulations using Eqs.(1)–(6). The spectrum calculated using only the properly normalized envelopes of the P and R branches of the rotational spectrum of the antisymmetric stretch of a CO2 molecule is shown by the pink dashed line. (g, h) The spectra of resonant 160-fs mid-IR pulses with a central wavelength of (g) 4.25 μm and (h) 6.20 μm transmitted through 1.5 m of atmospheric air. (i) The spectral profiles of the absorption coefficient and refractive index of the antisymmetric stretch of a CO2 molecule calculated with the full model of the antisymmetric stretch band of CO2 (in pink and blue, respectively) and using only a properly normalized envelope of this band, without individual rovibrational lines (in green and orange). (j) The absorption coefficient (pink) and refractive index (blue) of water vapor calculated with the full model of the H–O–H bending mode of a water molecule.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4202239&req=5

f3: Cross-correlation frequency-resolved optical gating traces (a–f) of resonant mid-IR pulses with a central wavelength λ0 equal to (a, b, c, d) 4.25 μm and (e, f) 6.20 μm and an input pulse width τ0 = 160 fs transmitted through 1.5 m of atmospheric air: (a, c, e) experiments and (b, d, f) simulations using Eqs.(1)–(6). The spectrum calculated using only the properly normalized envelopes of the P and R branches of the rotational spectrum of the antisymmetric stretch of a CO2 molecule is shown by the pink dashed line. (g, h) The spectra of resonant 160-fs mid-IR pulses with a central wavelength of (g) 4.25 μm and (h) 6.20 μm transmitted through 1.5 m of atmospheric air. (i) The spectral profiles of the absorption coefficient and refractive index of the antisymmetric stretch of a CO2 molecule calculated with the full model of the antisymmetric stretch band of CO2 (in pink and blue, respectively) and using only a properly normalized envelope of this band, without individual rovibrational lines (in green and orange). (j) The absorption coefficient (pink) and refractive index (blue) of water vapor calculated with the full model of the H–O–H bending mode of a water molecule.
Mentions: Typical FWM XFROG traces of mid-IR waveforms modulated by the rovibrational modes of carbon dioxide molecules and atmospheric water vapor are shown in Figs. 3a–3f. The difference between these traces and the XFROG traces of mid-IR pulses tuned off all the molecular resonances (Figs. 2b, 2c) is striking. Unlike off-resonance FWM XFROG traces, determined by an appropriate convolution of the mid-IR and reference pulses, the XFROG traces of mid-IR pulses tuned on a resonance with molecular modes exhibit well-resolved fringes along with a complex ring-down structure.

Bottom Line: Here, we show that, with a combination of advanced ultrafast technologies and nonlinear-optical waveform characterization, time-domain techniques can be advantageously extended to the metrology of fundamental molecular motions in the mid-infrared.In our scheme, the spectral modulation of ultrashort mid-infrared pulses, induced by rovibrational motions of molecules, gives rise to interfering coherent dark waveforms in the time domain.These high-visibility interference patterns can be read out by cross-correlation frequency-resolved gating of the field in the visible generated through ultrabroadband four-wave mixing in a gas phase.

View Article: PubMed Central - PubMed

Affiliation: 1] Physics Department, International Laser Center, M.V. Lomonosov Moscow State University, Moscow 119992, Russia [2] Russian Quantum Center, ul. Novaya 100, Skolkovo, Moscow Region, 1430125 Russia.

ABSTRACT
When coupled to characteristic, fingerprint vibrational and rotational motions of molecules, an electromagnetic field with an appropriate frequency and waveform offers a highly sensitive, highly informative probe, enabling chemically specific studies on a broad class of systems in physics, chemistry, biology, geosciences, and medicine. The frequencies of these signature molecular modes, however, lie in a region where accurate spectroscopic measurements are extremely difficult because of the lack of efficient detectors and spectrometers. Here, we show that, with a combination of advanced ultrafast technologies and nonlinear-optical waveform characterization, time-domain techniques can be advantageously extended to the metrology of fundamental molecular motions in the mid-infrared. In our scheme, the spectral modulation of ultrashort mid-infrared pulses, induced by rovibrational motions of molecules, gives rise to interfering coherent dark waveforms in the time domain. These high-visibility interference patterns can be read out by cross-correlation frequency-resolved gating of the field in the visible generated through ultrabroadband four-wave mixing in a gas phase.

No MeSH data available.


Related in: MedlinePlus